3rd Gen Differential and Manual Transmission (6MT) Fluid Change

This is my first post on TW. Just bought a TRD Pro a couple months ago, and I'm loving it. I've been skimming TW and learning for a few weeks now. This post is exactly what I've been looking for (excellent job OP!) as I'm about ready to swap out all of my fluids after 2,000ish miles. I think I found a good alternative to the LF transfer case oil (I think it was from another post here in TW actually):

RAVENOL J1C1003 SAE 75W Manual Transmission Fluid - MTF-3 Full Synthetic (1 Liter)
http://www.ravenolamerica.com/transmission-fluid/75w-manual-transmission-fluid-ravenol-mtf-3/

RAVENOL J1C1003 SAE 75W Gear Oil - MTF-3 Full Synthetic (1 Liter)

https://smile.amazon.com/gp/product/B00QPCL7ZE/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

Has anyone used this in transfer case?

 

I've seen it pop up every once in awhile for German cars but haven't researched it enough. I'm curious about it as well.

OA

 

http://www.fjcruiserforums.com/forums/maintenance-tech/129144-2010-oil-viscosity-transfer-case.html

Looks like some guy got an analysis of the OEM t-case oil in this link.
I think the big issue is not GL-5 for two reasons: sulphur that can corrode synchros and GL5 is much more slippery than GL-4 so messes with synchros. 4hi apparently has synchros in a chain driven yota t-case.
http://www.mobil.com/english-US/Passenger-Vehicle-Lube/pds/GLXXMobil-1-Syn-Gear-Lube-LS-75W90
mobil 1 says it protects copper alloys (brass) from corrosion so.?!#?


I think the next things are the viscosity items one needs to look at are listed as a few different names.

kinematic viscosity either in mm2 or centistokes (cST) at 40 and 100 degrees centrigrade (how well is flows and addresses shear)
and absolute viscosity. that's just an index of how the fluid holds up internally to force. that's usually given in poise (p)
They will also give you viscosity index, but that's just how stable the fluid is to temperature change. the larger the VI, the less the viscosity swings with temperature change.

so at least you know if you see a cST or a P, you know what the numbers are in reference to. cST is going to be lower at 100deg vs 40deg. I've seen 100deg around 8-11 and then 40 deg varying from 40-100 cST for different GL4 fluids I've looked at. lower cST means flows better. I've also seen the absolute viscosity range between 186-192p at 100 deg but haven't seen absolute viscosity at 40 deg.

cST is a measure of how well it flows. it's the poise that goes into shear protection if I remember my fluid properties correctly
So you'll usually see something like this on a chart:

40 deg: 120 cSt
100 deg: 10.6 cSt
Brookfield viscosity at -40: 300 p (you MIGHT see cP for centipoise)

I haven't seen the viscosity for ravenol

here is an example of GL5 75-90
https://www.redlineoil.com/product.aspx?pid=133&pcid=4

and GL4 75-90 from redline

https://www.redlineoil.com/product.aspx?pid=46&pcid=7

This is the fact sheet for the amsoil mt that was used by OP

Kinematic Viscosity @ 100 ̊C, cSt (ASTM D445) 13.9
Kinematic V iscosity @ 40 ̊C, cSt (ASTM D445) 87.6
V iscosity Index (ASTM D2270) 162
Brookfield Viscosity @ -40 ̊C, cP (ASTM D2983) 34,320 (cP, so its 343 poise)

For comparison, 0w-20 motor oil is around 2-4 poise (but it's the high temp high shear that matters in engine oil).

What's interesting is that the brookfield viscosity is 3x higher in all these fluids compared to the fluid in the FJ in the post, which was around 100.

The difference between poise is honey 100 poise, ketchup 500 poise. So, doesn't seem like a big deal. it's not like an exponential increase to go from 100-300.

To give a point of reference: there is something in all of us that goes from 126 to 300 poise as we move: joint fluid/synovial fluid. So, if the change doesn't mess up something as sensitive as cartilage, it shouldn't mess with metal.

So, It doesn't seem like going from 100 to 300 p is a big deal. joint fluid can actually range from 100-1000P and range between 126-300 as we move, if I remember correctly from my joint classes.

I'm thinking I'll go with redline or amsoil because I can get those off Amazon.

I'm driving this to analysis to paralysis I think. But the issue is, if I mess up my knee and need surgery, it's $500 and insurance covers the rest. If I mess up the t-case, damn, that's more than a grand! I have health insurance, truck doesn't.

 

I agree with more frequent changes than are ( not even listed in the Toyota owners manual maintenance guide ). Only lube differential at 15 k ( when some early 2016's were sent out with inappropriate assembly lube to begin with. ) I may have a different mileage / time maintenance schedule than you but similar and far and away above the factory recommended schedule but not Never or at 90,000 miles if you want to be a fanatic, as per my dealership shop foreman.

Don't forget the transfer case ! All driveshaft points. Maybe even the clutch and brake fluid at some point???? ( though I have the same brake fluid in my 1988 Harley hydraulic brake system since it was built exactly 29 years ago and has near about 34,000 original miles on it now )

Personally I plan to use all Toyota lubricants but the jury is still out on that. If I can find a better lubricant like maybe a better synthetic blend I may use that.

I bought my 2016 TRD sport with only $1,000 down and about $2,500 for other options. My monthly note is high. So I may trade mine in or sell it privately at 36,000 miles/ 3 years and use the money to pay off the remaining loan and use the remaining cash as a much better down payment than I just used for this one now. Then purchase an identical in every way a new 2019 or 2020 TRD sport in black with manual shift again with a much lower monthly note and all new warranty. ( if they still offer manual shift vehicles

But as I've done likewise to all my previous cars I keep it better than new in case as happened once, have to keep it until I run it into the ground ( or my wife crashes it into and through the wall of my doctors office! )
Dannyblues

 

I saw a video on you tube of a guy changing his fluids and he was shocked to find that even though he didn't use 4 WD much the transfer case fluid was thick black ugly molasses that even heavily coated the drain plug ! So I'd include that too. Dannyblues

 

I don't know why you had to top off those fluids. Even when full according to factory the amount of fluid needed is listed and generally such as the case of the transmission the correct amount of fluid comes only up to and just below the fill plug.

Whether it's true or not someone posted that over filling the diffs may result in pressure inside when they heat up. I don't know if this is true but I would drain and refill only with the correct type and amount of the recommended fluid or better as long as it maintains your warranty or better protects that part of the large investment you've made in your Tacoma.

Just passing along a post.

Also as I said my Tacoma is a large investment. I paid more for my 2016 TRD than I did for my first house. No kidding! So even if the lubricant is expensive I'll purchase it unless I can find a better one at a cheaper price.

I also plan to follow a much more frequent maintenance schedule than recommended by Toyota with the OEM parts and fluids unless I find better ( since I'm not an automotive engineer or as knowledgeable as some I'll probably stick with all OEM stuff ).
Dannyblues

 

After 32 years I as a Pepsi cola vending/ refrigeration/ fountain systems mechanic and coors beer plumber I can tell you the theory behind refrigeration and how soda equipment works but understanding your brilliant post makes me feel like an automotive moron.

Thanks for posting such a positively knowledgeable post. It will take me time to ingest it. I got the general meaning but that's all. I stick with OEM fluids at this point at least until I'm knowledgeable enough to know better. Then I can go out in confidence and purchase a cheaoer and more superior product.

Much appreciated. Dannyblues

 

Wow so I read your post several times and I'm still confused .... should I be using gl4 or gl5 in the transfer case? The reason I ask is I drained both diffs and the transfer case and used 75w/90 mobil one in everything.

 

The reason why I topped off the rear diff and front diff was because they were low on fluid from the factory....rear--about 1 1/2 cups. front about 1/2 cup. I filled to the hole and let it drip till it stopped....

 

Wow! How did you know they were not filled properly??? Was it just a routine maintenance check or did you hear a whine? Or did you find out online or on this site??? My 2016 TRD was made in June 2016. I heard driveshaft issues regarding lubrication and I had the stuck shifter issue. TSB-0088-16. Corrected by dealer after I informed him of the service bulletin. Thanks for that information. Dannyblues

 

So... I think most people say it's OK to use GL5. But, GL5 is designed for splash lubricated hypoids, so apparently it's a bit more slippery. The problem with more slippery fluids in a t-case is that there are synchronizers that match the speed of the front drive shaft so 4x4 can be shifted on the fly on some 4x4 systems, according to engineering colleagues. According to these guys, if the fluid is too slippery, it causes problems with the synchros because they can slip. GL4 is less slipper and is OK for manual transmissions with synchros that have to speed up/slow down. So, the idea was that GL4 is better than GL5 for 1) lower sulfur 2) less slippy. But I guess the sulfur's not a big problem with mobil 1 because of how the sulfur is formulated/compounded and was more of a problem with older sulfur formulations, so it seems like it's not something to worry much about?

my thought is, mobil 1 75-90 GL5 is $11. amsoil and red line GL4 75w or 75W85, 75W90 are both around $15/16. why not pay the extra 4-5 bucks for peace of mind.

But it also seems like there are plenty of people who appear to be running GL-5 mobil 1 without problems. I'm thinking if you already put the mobil 1 in, why not just leave it, but if you haven't changed it yet, use GL4?

I'm going to go with GL4 since I have not yet changed it out yet. I have a bottle of GL5 from valvoline (synpower) that I'm just going to save and use in my car.

 

So if I am going to see/feel some negative effects it will be when engaging 4wd?... I guess I'll dump the transfer case and replace the Mobil one with a gl4 that you recommend above, thanks.

 

you overestimate sir.

I'm an automotive dunce.

I change fluids, maybe some driveline parts/brakes that use a big hammer.
I can remove grills and spray rust-oleum on them.
Give me an electrical diagram and I can't make heads nor tails of it.

I understand fluid properties and mechanics (not automotive) as it relates to the human body. just trying to use what I know of fluid and chemical properties to figure out this fluid issue because again, truck doesn't have health insurance. Just trying to shed some light on fluid viscosity and ingredients in case people want to shop around. i don't like not knowing what's in something.

this was a result of a two hour discussion that should have been a 2minutes "yes or no" that I had with some engineering colleagues that know a thing or two about lubrication. I walked out thinking "I just wanted a yes or no on fluid". instead we had a two hour discussion on fluid properties and chemical properties. Welcome to my world of analysis to paralysis. After the discussion, I understood why these guys know so much about lubrication, because there's no way in hell these guys are getting laid.

 

Don't let Obama hear you say that or next thing you know we'll all have extra deductions showing up on our paystubs for that insurance haha. But seriously, took me a bit on your post to realize I had mostly no idea what I was reading lol.

 

If a person intends to keep their truck for at least 100K miles (that you put on it), using an oil analysis lab such as Blackstone is a very good idea, as you can monitor your engine/trans/diffs/TFer case for abnormal wear and catch a developing problem before it becomes a full blown disaster.

I used Amsoil products in all parts on both my previous Ford and Dodge diesel pickups for over 20 years, and also sent samples to Blackstone Labs with every fluid change throughout that same 20+ year period. It does add a bit to the overall cost of changing fluids, but it can save you $$$ in the long run if you plan to keep the truck for a good many miles.

I do not have any personal use with any other brand of synthetic lubricants, such as Redline or Royal Purple, so I can not make any comparisons between brands.

 

I started using Blackstone Labs in the past year and find the info useful. I won't do it every change but probably every year or so.

 

Well, I read about the low trannys on here and the dealer would not check it physically "on their dime", so I checked it myself...1 1/2 qt. low. Then got the TSB done on tranny and filled it..... THat fixed the "stuck in 4th while in cruise" issue.

Then I checked the U bolts.... had to torque 7 out of 8 to get them to 52 FTLB. Checked the grease zerks on driveshaft... 7-8 pumps each.... WTF Toyota...????

So, after all that, I can't trust Toyota.....I had to get under there again and check the diffs and T case..... both diffs low.!! Never had the "whine"...

Mt truck now runs real fine...."like a well oiled (by me) machine"...!! I love my little "Punkin'" now....

 

I hate to be one of "those guys" that complain, but if they denied to check my trans fluid and then I found it to be that low myself, I would've flipped on them. Luckily my dealer manually checked the fluid and did the rev 1 tsb when I told them the trans was too "indecisive" lol.

 

I decided that the best thing to do was to look after MY truck MYSELF, and if I need warranty work, then I have not pissed them off to this point and "may" get a reasonable response to the warranty issue.... If I "gave 'em shit" over the low tranny thing....I'd have to go elsewhere from there on and I do not have much choice here...!! I'm much happier knowing that it is done right (because I did it)...!!

 

What dealer dood? I ask cuz we're somewhat local...PM me if you don't wanna throw it out in public